1. Field of the Invention
The present invention relates in general to a wire coiling machine for forming a wide variety of different types of coil springs including, but not limited to, tension and compression springs. More particularly, the present invention pertains to a computer controlled wire coiling machine that is controlled to permit programming of a wide variety of springs.
2. Background Discussion
Various types of wire coiling machines are generally known in the art. By way of example, refer to U.S. Pat. No. 1,266,070 to Sleeper and U.S. Pat. No. 2,175,426 to Blount et al. Each of these patents show wire feed rollers that are in constant engagement with the wire but are driven intermittently by means of a reciprocable gear segment of a variable throw. For further background in connection with the invention herein, also refer to the following U.S. Pat. Nos. owned by the instant assignee herein: 4,372,141; 4,402,204; 4,416,135; 4,524,797; 4,528,831; and 4,607,513. These prior art wire coiling machines, such as the one described in U.S. Pat. No. 4,402,204 employ a cam shaft requiring a plurality of cams for controlling certain wire coiling functions. The cams are rotated at a cam shaft speed rate and because many of the operations carried out at the workstation are controlled from the cam shaft, the functions carried out are for the most part inter-dependent functions. These machines thus do not permit individual control of many of the parameters controlled at the workstation. Moreover, the machines described in these patents are not at all computer controlled.
The aforementioned U.S. patent application Ser. No. 07/116,068, filed Oct. 30, 1987 does describe a computer controlled coiling machine and generally teaches the use of separate control motors for wire feed as well as for pitch and diameter tool motions.
However, the system described in this related co-pending application contemplated a velocity feed profile that is substantially constant once the feed is brought up to speed. The operating speed in this system is limited by certain tool motions that occur and once the tool motions for a particular spring have been established then this likewise establishes the constant operating range of wire feed. Such a system has the characteristic of a relatively poor spring production rate.